1. Field of the Invention
The present invention relates to an electronic part with attached lead wires and more particularly to an improvement in the shape of the lead wires.
2. Description of Related Art
FIG. 4 shows an electronic part 1 with attached lead wires which is related to the background of the present invention. The electronic part 1 has a main body 2 in the shape of a disc, for example. Electrodes 3 and 4 (the electrode 4 is shown in FIG. 5) are formed respectively on two opposed main surfaces of the main body 2.
The electrodes 3 and 4 are connected electrically with lead wires 5 and 6, respectively, by solder 7 which is shown by an imaginary line in FIG. 4. Dip soldering for example is used in this soldering operation. It is noted that the solder may be applied to the lead wires 5 and 6 beforehand and then the wires may be soldered by melting the solder, instead of dip soldering. The two lead wires 5 and 6 are led out respectively in the same direction. Further, the lead wires 5 and 6 have crossing portions 8 and 9 which extend in suitable directions so as to cross each other at the parts where they are connected with the electrodes 3 and 4.
Further, a resin sheath 10 shown by an imaginary line in FIG. 4 is applied so as to cover the main body 2.
The electronic part 1 with the attached lead wires is supplied from an elongated holder 11 wherein a plurality of such parts are distributed in the longitudinal direction. The holder 11 has a carrier tape 12 and an adhesive tape 13 which is adhered to it. The holder 11 holds the electronic parts 1 by holding their lead wires 5 and 6 between the carrier tape 12 and the adhesive tape 13.
The processes of working on the lead wires 5 and 6, inserting the main body 2 between the lead wires 5 and 6, soldering the lead wires 5 and 6 to the electrodes 3 and 4, and applying the resin sheath 10 are normally carried out while the lead wires 5 and 6 are held by the holder 11. Then, in a stage of mounting the electronic parts on a circuit board, the lead wires 5 and 6 are cut along a cut line 14 for example and the electronic parts 1 with the attached lead wires 5 and 6 are separated from the holder 11.
This structure of an electronic part can be applied to a capacitor, for example. In this case, the main body 2 is made from dielectric ceramic. Electrostatic capacitance is created between the opposed electrodes 3 and 4 and is accessed via the two lead wires 5 and 6.
FIG. 5 is a right side view of the electronic part 1 shown in FIG. 4. A problem to be solved by the present invention will be explained with reference to this figure.
At the location where the lead wires 5 and 6 form the cross portions 8 and 9 at the parts thereof connected respectively with the electrodes 3 and 4 as described above, it is possible for each of the end portions of the cross portions 8 and 9 to become detached respectively from the electrodes 3 and 4, thereby creating gaps 15 and 16 between each of the end portions of the cross portions 8 and 9 and each of the electrodes 3 and 4 as shown in FIG. 5.
The gaps 15 and 16 are apt to be created when a thickness of the main part 2 is relatively large.
In order to solder the cross portions 8 and 9 to electrodes 3 and 4, bend portions 17 and 18 are often created in the lead wires 5 and 6 as shown in FIG. 5 to create distances 19 and 20 of about 0.5 mm to 1.0 mm for example between the lead wires 5 and 6 and the peripheral portion of the main body 2, in order to prevent deterioration of the withstand voltage of the electronic part 1 which otherwise occurs when the solder 7 (see FIG. 4) enters around the peripheral surface of the main body 2. However, the creation of the bend portions 17 and 18 in the lead wires 5 and 6 as described above is apt to cause the gaps 15 and 16 to be created between each of the end portions of the cross portions 8 and 9 and the corresponding electrodes 3 and 4.
Further, when the main body 2 is made from ceramic, the ceramic often warps when it is sintered during its fabrication, causing both sides of the main body 2 to be curved or irregular. The use of such a curved main body 2 also causes the gaps 15 and 16 to be created.
If the gaps 15 and 16 are thus created, the cross portions 8 and 9 barely contact the electrodes 3 and 4, having only a point-contact at bases 21 and 22 thereof. Therefore, the main body 2 is apt to rotate, centering on the contact point with the base 21 or 22, and the positional relationship between the lead wires 5 and 6 and the main body becomes instable. Thus, it is possible for the main body and the lead wires to be soldered even though they are in an inadequate positional relationship.